From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net] tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on
 established sockets
Date: Thu, 12 Apr 2018 21:50:02 -0400 (EDT)
Message-ID: <20180412.215002.623918426728104388.davem@davemloft.net>
References: <20180411213628.194344-1-edumazet@google.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com
To: edumazet@google.com
Return-path: <netdev-owner@vger.kernel.org>
Received: from shards.monkeyblade.net ([184.105.139.130]:60442 "EHLO
        shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1752170AbeDMBuE (ORCPT
        <rfc822;netdev@vger.kernel.org>); Thu, 12 Apr 2018 21:50:04 -0400
In-Reply-To: <20180411213628.194344-1-edumazet@google.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

From: Eric Dumazet <edumazet@google.com>
Date: Wed, 11 Apr 2018 14:36:28 -0700

> syzbot/KMSAN reported an uninit-value in tcp_parse_options() [1]
> 
> I believe this was caused by a TCP_MD5SIG being set on live
> flow.
> 
> This is highly unexpected, since TCP option space is limited.
> 
> For instance, presence of TCP MD5 option automatically disables
> TCP TimeStamp option at SYN/SYNACK time, which we can not do
> once flow has been established.
> 
> Really, adding/deleting an MD5 key only makes sense on sockets
> in CLOSE or LISTEN state.
 ...
> Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: syzbot <syzkaller@googlegroups.com>

Applied and queued up for -stable.